ABOVE: A bullplug designed with a shear-off valve (left) can help improve tube trailer safety and potentially avoid dangerous accidents (right).
While the majority of tube trailers and skid containers already have a design that includes a rigid, protective framework, accidents have occurred that resulted in a tube trailer’s exposed valves being sheared off, with the result being release of hydrogen gas followed by a fire. In a recent accident, a tube trailer got rear-ended by a garbage truck. Due to the weight and height of the garbage truck it was able to make contact with the rear valves. The valve’s pressure-holding components on this trailer were exposed outside of the bullplug into which the valve is inserted. Several valves sheared and flammable gas was released. If the integrated bullplug/valve had been installed, the valve handle would have sheared at impact, but the valve’s internal components holding the gas pressure would not have been impacted because they are sheltered by the substantial steel structure of the bullplug assembly.
A uniquely designed, integrated bullplug/valve has recently been introduced to the compressed gas industry. When installed in the rear end of jumbo and superjumbo tube trailers transporting a gas that is authorized to have only one pressure relief device installed on the front end of the equipment, installation of this device in the rear is ideal for enhancing safety, reducing leaks, and insuring compliance with Compressed Gas Association (CGA) Technical Bulletin TB-25, Design Considerations for Tube Trailers. It can also be used on multiple-element gas containers (MEGCs) shipping product overseas. The product protects the valve internal components from damage or leakage in the event of an accident, particularly a rear end collision or rollover during transportation, when the valves are closed, as is required by DOT regulation.
The valve’s sacrificial hand wheel has a machined shear point to allow shearing with no damage to the valve’s internal, pressure-containment parts. Other similar designs do not permit easy removal of the gas trapped in the tube after the valve is sheared. With this device a simple replacement of the hand wheel gets the valve operational within minutes in order to allow unloading of the gas and safe evaluation of the accident damage. The CGA outlet connection is machined directly into the face of the bullplug to eliminate costly thread leaks, which are common in tube isolation valves. The bullplug body is manufactured from 304L stainless steel and, thus, should never need replacement. The substantial bullplug body provides protection to the valve’s internal, gas tight components. The valve internal components are field replaceable and they are the same components used in the Sherwood GV series, which has a proven track record in industrial gas service.
The Federal Hazardous Materials Regulations in Title 49 of the Code of Federal Regulations (which are written and enforced by the various branches of the U.S. Department of Transportation [DOT]) stipulates in 49 CFR § 173.301(i)(2) that: “Seamless DOT specification cylinders longer than 2 m (6.5 feet) are authorized for transportation only when horizontally mounted on a motor vehicle or in an ISO framework or other framework of equivalent structural integrity in accordance with CGA TB-25.” This new integrated valve/bullplug design complies with TB-25, which, among other factors, mandates protection from a rear end collision or rollover. If a valve is not adequately protected and shears during an accident the release of the gas contained within the tubes on the trailer could be catastrophic, especially if the gas released was flammable or toxic. The framework, cabinet or other protective steel cage can be designed to protect the cylinder valve from impact during an accident, but this adds weight to an already heavy tube trailer where safety and weight reduction are of primary importance. The integrated bullplug/valve device provides the same or greater protection without adding weight to the tube trailer.
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To learn more about the integrated bullplug/valve please contact FIBA Technologies, Inc. at (508) 887-7100 and ask for customer service. Call this same number if you want to purchase these parts or have them installed in orders placed with FIBA or in equipment being requalified by FIBA, just specify FIBA Part # M25-16169 X-X on your next purchase order!